Where the heart function is chronically insufficient, there may be a need to permanently aid the heart function. Heart failure (HF), more often called Congestive Heart Failure (CHF), is in general a condition where the heart is unable to support the body tissue with its metabolic demands and to sustain adequate blood pressure and cardiac output. The term Congestive relates to a congestion of blood and fluids in front of the pumping ventricles as a result of insufficient forward pumping, most often caused by disease of the left ventricle muscle. A peculiarity of heart cells is that they do not regenerate after damage or cell death, thus conditions have a tendency to worsen rather than heal after heart cell damage. There are many reasons for heart cell death, the most common cause is ischemic heart disease, a condition where the arteries feeding the heart muscle get clogged, causing myocardial infarctions (MI). Viruses may damage the muscle cells, and some diseases, for instance cardiomyopathy have unknown reasons. End stage of long standing high blood pressure may also cause end stage heart failure. Heart strengthening drugs like digoxin or treatment with diuretics help for a while, but are all only treating symptoms. CHF is a progressive untreatable, disabling and finally a deadly condition. According to the American Heart Association homepage, there are in the US at present more than 5 Million patients living with CHF and 550 000 are added every year. 40000 patients in the US are in such a bad state that only a heart transplant will keep them alive. However, due to the limited number of suitable organs only 2500 transplants are done yearly in the US. One may extrapolate the numbers for the rest of the industrialized world.
Total artificial heart, where the whole native heart is excised and replaced with a mechanical device was introduced in the 1960's by DeBakey, in the 1980's by among others Jarvik and recently by Copeland (CardioWest, Total Artificial Heart). However, these devices are still based on complex designs and are very invasive to install in the patient. Failure in operation of the device is fatal.
There are other techniques supporting only the failing left ventricle, known as left ventricle assist devices (LVAD). The most popular LVADS are the Novacor and the HeartMate devices. Common for this devices is the demand for major open heart surgery utilizing extracorporeal circulation by means of a Heart- and Lung-machine while stopping (or excising) the heart. They are bulky devices, a Novacor weights 1.800 grams, a HeartMate 1.200 grams. There are smaller axial flow pumps available nowadays, the HeartMate II, the Jarvik 2000 and the MicroMed DeBakey VAD. However, major open heart surgery is still necessary to install and connect these devices to the left ventricle cavity and the aorta by means of large vascular grafts. The mentioned devices have almost exclusively been used as a bridge to a heart transplant due to high frequency of complications, some of which are caused by the large amount of foreign material, high mortality and limited durability. Their use has also been limited because of high prices of up to 150 000 $ only for the device.
In U.S. Pat. No. 5,957,977 an activation device for the natural heart is disclosed. The activation device has a stint for placement within the interior volume of a natural heart adjacent cardiac tissue thereof. The device also includes a yoke for placement around a portion of the exterior surface of the natural heart in general alignment with the stint and connected to the stint by at least one cord (surgical thread). By means of multiple parts that are assembled during surgery, a cage is created where half of the cage is inside the heart and the other half outside. Within the cage a heart chamber, e.g. the left ventricle is completely locked in. By means of hydraulic power underneath the external part of the cage, compression on the chamber is achieved from the outside. The inner half avoids that inner heart structures may give away while compressing from the outside. However, the device is very invasive, as it requires a connection between the interior of the heart and the exterior of the heart. Moreover, extensive open heart thoracic surgery is required to position the device in the patient, none of which involves surgery of the mitral valve. Furthermore, the device is not designed for action synchronic with the natural heart cycle.
None of the devices for permanent implant previously described are feasible for minimal invasive catheter based insertion. On the contrary, they all involve major open heart surgery. There is a need and demand for simpler devices. It is one scope of the here presented invention to omit major cardiac surgery and to allow positioning of an implant with catheter technique or by minimal access surgery.
Moreover, health care is permanently searching for improved devices and methods.
Hence, there is a particular need of an improved system and/or method for permanently enhancing or assisting left ventricular pump function of a heart of a patient. The system is advantageously not interfering with the cardiac cycle of the heart. Major open heart surgery is desired to be avoided. Even more advantageous would be if at the same time leaking heart valves could be repaired. It is also desired to avoid implantation of large surfaces of foreign material in the heart. Advantageously, the native valves, like the native mitral valve are preserved, when enhancing cardiac pump function with such devices.
Hence, an improved system and/or method for permanently enhancing or assisting left ventricular pump function of a heart of a patient would be advantageous and in particular allowing for increased flexibility, cost-effectiveness, long-term function, and/or patient friendliness would be advantageous.